Pressurized valve system for driving bristle tufts

ABSTRACT

The dental cleaning appliance includes an appliance body ( 30, 73 ) which has a bristle field housing ( 32, 52 ) and fluid within the housing. A flexible membrane ( 34 ) is positioned within the housing, or in a fluid-tight relationship ( 54 ) within an opening ( 60 ) in the housing. A fluid pressure system involving either a dual piston system ( 22, 24, 28 ) or a pump and valve system ( 70, 68, 68 ) provides pressure on the fluid, wherein the pistons move alternately, or the valves open and close alternately, in such a manner to produce alternating pressure above and beneath the membrane, moving the membrane and the bristle field toward and away from the teeth.

This invention relates generally to dental cleaning appliances, such astoothbrushes and mouthpieces, and more specifically concerns a systemfor driving the bristle tufts in those appliances toward and away fromthe teeth without producing cavitation sufficient to otherwise interferewith cleaning action.

In dental cleaning appliances, including both toothbrushes andmouthpieces, a particular bristle stroke useful for cleaning of dentalsurfaces is toward and away from the teeth in a tapping or lighthammering type of action. Various ways of producing this particularmotion are possible. However, one desirable way is by the use of fluidpressure. For effective cleaning action, a bristle stroke of between 0.9and 3.22 mm and a frequency between 100 and 300 Hz has been found to bedesirable. A known difficulty with such an arrangement, however, is thatuse of a pump to move fluid back and forth to produce the bristle strokeis both slow and energy consuming, as the inertial of the total fluidvolume must be overcome. Furthermore, it is also known that with such asystem the bristle tufts will move only very little, if at all, at thehigher frequencies, i.e. above 100 Hz, due to cavitation effects in thefluid which are created by the pump action. A system for accomplishingfluid pressure-driven bristle tuft movement within the desired frequencyrange of 100-300 Hz is thus desirable.

One aspect of such a dental cleaning appliance, comprising: an appliancebody, including a forward portion thereof having two separate interiorchannels and a bristle field housing at a distal end thereof; twomoveable piston members positioned in a fluid-tight relationship withinthe two channels; a flexible membrane positioned within the bristlefield housing, whereas the two channels extend above and below,respectively, the membrane, wherein fluid is present in the twochannels, without fluid communication between them; a plurality ofbristle tufts mounted on the membrane and extending sealingly throughthe housing; and an actuator assembly for moving the pistons alternatelyin a counter action within the two channels such that the membrane movesup and down, moving the bristle field toward and away from the teeth.

FIG. 1 is a simplified cross-sectional diagram showing one embodiment ofa fluid pressure-driven appliance showing a single tuft.

FIG. 2 is a simplified cross-sectional diagram showing anotherembodiment of a fluid pressure-driven tuft system.

FIG. 3 is a cross-sectional view of the embodiment concept of FIG. 1 ina complete toothbrush.

FIGS. 4A and 4B are cross-sectional views showing the bristle tuftaction of the toothbrush of FIG. 3.

FIG. 5 is a cross-sectional view of the embodiment concept of FIG. 1 ina mouthpiece.

FIG. 6 is a cross-sectional view of the embodiment concept of FIG. 2 ina complete toothbrush.

FIGS. 7A and 7B are cross-sectional views showing the bristle tuftaction of the toothbrush of FIG. 6.

FIG. 8 is a cross-sectional view of the embodiment concept of FIG. 2 ina mouthpiece.

FIG. 1 shows a first embodiment of a fluid pressure system for driving abristle field toward and away from the teeth of a user, producing atapping action against the teeth for cleaning thereof The fluid pressuresystem can be used for moving either a toothbrush bristle field or amouthpiece bristle field. FIG. 1 shows a brushhead portion 12 of atoothbrush and a bristle field 14 which for purposes of clarity includesonly a single bristle tuft. Typically, a bristle tuft will include 90 orso individual bristles, while the bristle field for a toothbrush willtypically include approximately 20 bristle tufts. While FIG. 1 shows abrushhead 12 which is more suitable in a toothbrush, similararrangements can be made for a mouthpiece, as discussed in more detailbelow.

Brushhead portion 12 includes a neck section 15 which is divided intotwo channels 18 and 20 by a longitudinal member 22, positionedapproximately midway between upper and lower neck section walls 23 and25. Positioned in channels 18 and 20 in a fluid-tight relationship arepistons 22 and 24 which are moved back and forth by an actuation systemshown generally at 28 positioned in a body portion 30 of the toothbrush.

Within a bristle field housing 32, which is located at the distal end ofbrushhead 12 and in fluid communication therewith, is mounted a flexiblemembrane 34. Membrane 34 in the embodiment shown is 10 mm wide by 20 mmlong, which is approximately the size of a conventional toothbrushbristle field, and is approximately 0.1 mm thick in the embodimentshown. Membrane 34 is made of flexible rubber or other elastomericmaterial. The group of individual bristle tufts, illustrated by thesingle bristle tuft 14 shown, comprising a bristle field, are sealed tothe membrane 34 and, to prevent fluid leakage, are sealed to the bristlefield housing 32 at 35 as well. Positioned to the brushhead side ofpistons 22 and 24 is fluid such as water, in both channels 18 and 20,while to the left of pistons 22 and 24 is air.

In operation, the pistons 22 and 24 move exactly counter-directionallyto each other, i.e. 180° apart. As one piston moves to the right, theother piston moves to the left, and vice versa. When lower piston 24,for instance, moves to the right, an overpressure is created beneathmembrane 34, due to the volume of channel 20 decreasing. At the sametime piston 22 is moving to the left, resulting in under-pressure abovemembrane 34. This results in membrane 34 and the bristle tuft fieldmoving upwardly in FIG. 1, in the direction of the teeth. Typically, thestroke will be approximately 3.2 mm, although the stroke could besomewhat different, i.e. within the range of 0.9-3.2 mm, and stillproduce effective cleaning

Alternately, as upper piston 22 moves to the right toward the bristlefield housing, creating an over-pressure on the upper surface ofmembrane 34, piston 24 will be moving to the left, resulting in anunder-pressure on the lower surface of the membrane. This results in themembrane moving downwardly, with the bristle tuft field thus moving awayfrom the teeth.

Continued repetitive action of the pistons 22 and 24 results in a rapidback-and-forth movement of the bristle tuft field, producing a tappingor light hammering-type action against the teeth, producing effectivecleaning The use of a double piston arrangement, with a consistentpressure (above ambient) within channels 18 and 20 and within thebristle tuft housing, prevents cavitation from occurring to anysignificant degree in fluid present in the mouth, thereby permittinghigher bristle field frequencies, i.e. within the range of 100-300 Hz,with an effective stroke length.

FIG. 3 shows a more complete toothbrush 35. It includes a toothbrushbody 36 and a brushhead 37 with a bristle tuft housing 38 at the distalend of the brushhead, a plurality of bristle tuft assemblies 39,positioned within housing 38 and mounted for up/down movement relativethereto. The bristle tuft holder portion of the bristle tuft assembly 39is sealed relative to the bristle tuft housing 38. The bristle tuftholder further is connected to a flexible membrane 40 positioned in thehousing 38.

Two channels 41, 42, filled with fluid, extend for the length of thebrushhead 37, into bristle tuft housing 38. At the proximal ends of thefluid channels are pistons 43, 44, as in the above embodiment. They arecounter-driven, typically with a 0.5 mm stroke, to press against thefluid in the channels, with the pressure always above ambient.

The pistons 43, 44 are moved separately by a linear actuator assembly45, slidably moving along a track or a trolley 49 or the like. Thesystem has a controller 47 with a power source 48. FIGS. 4A and 4B showthe movement of the bristle tuft assemblies 39, up and down withmembrane 40 as the pistons move counter to each other.

A mouthpiece embodiment is shown in FIG. 5. The mouthpiece shown at 80includes a rotating DC motor 82 with an eccentric, controlled by acontroller 84 with a power source 86. The motor 82 controls the movementof fluid alternately to an outer arch portion fluid connector 88 of themouthpiece and an inner arch fluid connector 90. A plurality of bristletuft assemblies 91 mounted on a flexible membrane, are located betweenthe inner and outer arch portions so that as fluid pressure increasesand decreases in alternating fashion on the membrane, movement of thebristle tuft assembly 91 toward and away from the teeth occurs,providing a tapping/light hammering action for cleaning of the teeth. Ahydraulic accumulator 100 keeps the fluid under positive pressure, toavoid cavitation.

FIG. 2 shows another embodiment for a fluid pressure-driven bristlefield. FIG. 2 shows a cross-section of a brushhead portion of atoothbrush which includes a bristle tuft housing 52. Housing 52 in theembodiment shown is 20 mm long by 8-10 mm wide and 7 mm deep. It is madefrom plastic material, approximately 1 mm thick. Internally of housing52 is a plate 54 which extends from side-to-side of the housing 52 butis positioned so that there is a space between ends 56 and 58 of theplate and the internal surface of housing 52. A fluid channel 56 is thusdefined between housing 52 and plate 54.

Housing 52 includes an opening 60 which extends from side-to-side of thehousing. In the embodiment shown, opening 60 is approximately 8 mm wide.Positioned in opening 60 is a flexible membrane 62. Membrane 62 is madefrom rubber or a similar flexible material, and in the embodiment shownis approximately 0.5 mm thick. A field of bristle tufts 64 is attachedto the membrane. This can be done by various means, including thermalwelding, gluing or molded into the membrane, or attached to a separateplastic sheet which in turn is attached to the membrane. In theembodiment shown, the bristle field is configured to be appropriate fora toothbrush embodiment.

Housing 52 includes two internal valves 66 and 68 which, in theembodiment shown, are rotational valves. Valves 66 and 68 are positionedbetween the inner surface of housing 52 and plate 54, adjacent theopposing edges of opening 60. Channel 56 is filled with fluid, withfluid access to membrane 60 being controlled by the position of valves66 and 68. In one embodiment, a fluid pump 70 is located in the housing.Alternatively, a fluid pump 71 could be located in the body 73 of theappliance with a fluid line 75 to channel 56.

In operation, the fluid pump maintains a constant fluid pumpingdisplacement in channel 56. The fluid could be liquid, such as water, orair. Valves 66 and 68 alternately open and close. When valve 66 isclosed, fluid pressure will increase to the left of valve 66 and withvalve 68 open, there will be an under-pressure (partial vacuum) createdunder membrane 62. The membrane will thus move inwardly of the housing,resulting in the bristle field 64 being pulled away from the teeth.

Alternately, when valve 66 is open and valve 68 is closed, anover-pressure is created beneath the membrane 62, forcing the membraneoutwardly from the housing, resulting in the movement of bristle tuftfield 64 toward the teeth.

An alternating action of valves 66 and 68 and hence membrane 62 resultsin a movement of the bristle tuft field 64 toward and away from theteeth, producing a tapping/light hammering action similar to that forthe toothbrush embodiment of FIG. 1. With the constant fluiddisplacement in one direction produced by the fluid pump and thealternating action of valves 66 and 68, a bristle tuft field frequencyof movement within the desired range of 100-300 Hz can be obtained,since there is little or no cavitation produced.

FIG. 6 shows a complete toothbrush 110 for the embodiment of FIG. 2,including a toothbrush body 111, a brushhead portion 112 and a bristletuft housing 114 at the distal end of the brushhead portion 112. A pump116 moves fluid through two channels 118 and 120 to valves 122 and 124,which alternately open and close by action of controller 126, via acontrol line 127, which also controls pump 116. A plurality of bristletuft assemblies 131 are mounted on a flexible membrane 128. A powersource 129 powers controller 126.

With valve 122 closed and valve 124 open, membrane 128 moves inwardly,with bristle tufts 131 moving away from the teeth, as shown in FIG. 7A.With valve 122 open and valve 124 closed, membrane 128 and the bristletufts move outwardly, contacting (tapping) the teeth for cleaningaction, as shown in FIG. 7B.

FIG. 8 shows a mouthpiece implementation 130 of the embodiment of FIG.2. A pump 131 controls the movement of fluid in a dental arch to valves132 and 134. The alternating action of the valves is controlled by acontroller 136, as is the pump 131. The fluid action relative to aflexible membrane 140 on which a plurality of bristle tufts 142 arepositioned will produce an in-and-out motion of the bristle tufts,toward and away from the teeth, producing a cleaning action.

Hence, several embodiments have been disclosed which provide a fluidpressure-driven action for moving a bristle tuft field at a desiredfrequency in the range of 100-300 Hz, wherein the embodiments aredesigned to substantially prevent cavitation, allowing the desiredfrequency to be achieved.

Although a preferred embodiment of the invention has been disclosed forpurposes of illustration, it should be understood that various changes,modifications and substitutions may be incorporated in the embodimentwithout departing from the spirit of the invention which is defined bythe claims which follow.

1. A dental cleaning appliance, comprising: an appliance body (30),including a forward portion thereof having two separate interiorchannels (18, 20) and a bristle field housing (32) at a distal endthereof; two moveable piston members (22, 24) positioned in afluid-tight relationship within the two channels; a flexible membrane(34) positioned within the bristle field housing, whereas the twochannels extend above and below, respectively, the membrane, whereinfluid is present in the two channels, without fluid communicationbetween them; a plurality of bristle tufts (14, 39) mounted on themembrane and extending sealingly through the housing; and an actuatorassembly (28) for moving the pistons alternately in a counter actionwithin the two channels such that the membrane moves up and down, movingthe bristle field toward and away from the teeth.
 2. The dental cleaningappliance of claim 1, wherein the frequency of movement of the bristletuft field is within the range of 100-300 Hz.
 3. The dental cleaningappliance of claim 1, wherein the stroke of the bristle tuft fieldmoving toward and away from the teeth is within the range of 0.9-3.22mm.
 4. The dental cleaning appliance of claim of claim 1, wherein thedental cleaning appliance is a toothbrush.
 5. The dental cleaningappliance of claim 1, wherein the dental cleaning appliance is amouthpiece.
 6. The dental cleaning appliance of claim of claim 1,wherein in operation one piston moves toward the bristle field housingwhile the other moves away from the bristle field housing, and viceversa.
 7. A dental cleaning appliance, comprising: an appliance body(73), including a bristle field housing (52) filled with fluid, whereinthe housing includes an opening (60) therein; a flexible membrane (62)positioned in the opening, the membrane having a fluid-tightrelationship with the housing; a bristle tuft field (64) mounted on themembrane; and a pump and valve system (70, 66, 68) for maintainingpressure on the fluid in the housing, the valves arranged within thehousing in such a manner and operating alternately such that fluidpressure alternately increases and decreases beneath the membrane,resulting in movement of the membrane and the bristle tuft field towardand away from the teeth.
 8. The dental cleaning appliance of claim 7,wherein the frequency of movement of the bristle tuft field is withinthe range 100-300 Hz.
 9. The dental cleaning appliance of claim 7,wherein the pump is located within the housing.
 10. The dental cleaningappliance of claim 7, wherein the pump (71) is located within theappliance body, with a connecting line (75) between the pump and thehousing.
 11. The dental cleaning appliance of claim 7, wherein the fluidwithin the housing is liquid.
 12. The dental cleaning appliance of claim7, wherein the fluid within the housing is air.
 13. The dental cleaningappliance of claim 7, including a rigid member (54) positioned withinthe housing, and wherein the valves are positioned between the rigidmember and the housing near opposite ends of the membrane, such that inoperation, the valves open and close alternately, resulting in analternating overpressure and underpressure beneath the membrane,producing the movement of the membrane and the bristle field toward andaway from the teeth.
 14. The dental cleaning appliance of claim 7,wherein the dental appliance is in the form of a toothbrush.
 15. Thedental cleaning appliance of claim 7, wherein the dental appliance is inthe form of a mouthpiece.